From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bryan O'Donoghue Subject: Re: [PATCH] efi/capsule: Make efi_capsule_pending() lockless Date: Fri, 06 May 2016 02:32:03 +0100 Message-ID: <1462498323.2404.8.camel@nexus-software.ie> References: <1462054407-9735-1-git-send-email-matt@codeblueprint.co.uk> <20160503090229.GC27540@pd.tnic> <20160503141201.GW2839@codeblueprint.co.uk> <20160504093031.GA4074@pd.tnic> <20160504114605.GH2839@codeblueprint.co.uk> <20160504122042.GB4074@pd.tnic> <20160504143531.GK2839@codeblueprint.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Kweh, Hock Leong" , Matt Fleming Cc: "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Ard Biesheuvel , joeyli , Borislav Petkov , "Ong, Boon Leong" , "Ong, Kean Chai" List-Id: linux-efi@vger.kernel.org On Thu, 2016-05-05 at 14:27 +0000, Kweh, Hock Leong wrote: > > -----Original Message----- > > From: Matt Fleming [mailto:matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org] > > Sent: Wednesday, May 04, 2016 10:36 PM > > To: Kweh, Hock Leong; Bryan O'Donoghue > > Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Ard > > Biesheuvel; > > joeyli; Borislav Petkov > > Subject: Re: [PATCH] efi/capsule: Make efi_capsule_pending() > > lockless > > > > On Wed, 04 May, at 02:20:42PM, Borislav Petkov wrote: > > > > > > Blergh. > > > > Wilson, Bryan, what kind of rollback support does the Intel Quark > > have if its > > firmware update is interrupted? > > > > The interruption could be for a number of reasons including power > > loss, or > > the example in this case, rebooting due to panic(). > > If not mistaken, the EFI firmware will not update a partially > uploaded binary due to checksum error. > User is required to re-update the efi capsule again on the next boot > up. > If the checksum fails then you're fine since you won't update flash. OTOH if you pull the plug we actually have a backup image - so even a partially flashed update shouldn't brick the system. How well that actually works i.e. is it tested in anger ? Meh - YMMV there fore sure. --- bod